Cysteine-loaded pH-responsive liposome/gold nanoparticles as a time-temperature indicator with instantaneous color change

The Effect of Gold Nanoparticle-Coated Dental Implants on Osseointegration - A Systematic Review

INTRODUCTION

Dental implants are used in dentistry to replace teeth, restore function and improve the quality of life for patients. Osseointegration is critical for the success of dental implants. Implant surface modification can enhance osseointegration. Gold nanoparticles have emerged as a promising coating material for dental implants owing to their unique physicochemical properties. We aimed to review published literature to assess the effect of gold nanoparticle coating in increasing osseointegration of dental implants.

DATA COLLECTION

A database search yielded a total of 14 articles between January 2011 till December 2021, of which nine articles were excluded and five studies met the inclusion criteria. All studies reported improved osseointegration outcomes with gold nanoparticle coating compared to uncoated controls.

RESULTS

The most reported osseointegration outcomes were bone-implant contact, removal torque (RTQ) and histological analysis of bone formation around the implant. Mean RTQ values for coated implants ranged from 6.7 to 52.8 Ncm, compared to 3.7-40.8 Ncm for uncoated controls. The histological analysis showed greater bone formation and density around the coated implants compared to uncoated implants. Gold nanoparticle coating appears to have a positive effect on osseointegration. The results of included studies suggest that gold nanoparticle-coated implants promote greater bone-implant contact (BIC), RTQ and bone formation around the coated implant than the uncoated implant.

CONCLUSION

With increasing usage of dental implants, the most prevailing concern among clinicians remains to be peri-implantitis. Peri-implantitis is observed despite the biocompatibility and osseointegration properties of titanium. Surface coatings with antimicrobial effectiveness can help in preventing the onset of peri-implantitis and bone loss, while increasing BIC.

Liposomes characterization for market approval as pharmaceutical products: Analytical methods, guidelines and standardized protocols

Liposomes are nano-sized lipid-based vesicles widely studied for their drug delivery capabilities. Compared to standard carries they exhibit better properties such as improved site-targeting and drug release, protection of drugs from degradation and clearance, and lower toxic side effects. At present, scientific literature is rich of studies regarding liposomes-based systems, while 14 types of liposomal products have been authorized to the market by EMA and FDA and many others have been approved by national agencies. Although the interest in nanodevices and nanomedicine has steadily increased in the last two decades the development of documentation regulating and standardizing all the phases of their development and quality control still suffers from major inadequacy due to the intrinsic complexity of nano-systems characterization. Many generic documents (Type 1) discussing guidelines for the study of nano-systems (lipidic and not) have been proposed while there is a lack of robust and standardized methods (Type 2 documents). As a result, a widespread of different techniques, approaches and methodologies are being used, generating results of variable quality and hard to compare with each other. Additionally, such documents are often subject to updates and rewriting further complicating the topic. Within this context the aim of this work is focused on bridging the gap in liposome characterization: the most recent standardized methodologies suitable for liposomes characterization are here reported (with the corresponding Type 2 documents) and revised in a short and pragmatical way focused on providing the reader with a practical background of the state of the art. In particular, this paper will put the accent on the methodologies developed to evaluate the main critical quality attributes (CQAs) necessary for liposomes market approval.

Enzymatic time-temperature indicator with cysteine-loaded chitosan microspheres/silver nanoparticles

A time-temperature indicator (TTI) based on acid-base reaction was developed by applying a new pH dye composed of cysteine-loaded chitosan (Cys-CS) microspheres and silver nanoparticles (AgNPs). It was hypothesized that cysteine released by the disintegration of Cys-CS microspheres at a critical pH would cause AgNPs to aggregate, leading to color change. Cys-CS microspheres were produced as water-in-oil (paraffin oil, MCT oil, soybean oil) emulsions according to the KOH addition method. An enzymatic TTI was made using glucose oxidase, glucose, and catalase. Only paraffin oil produced Cys-CS microspheres (average diameter, 335 ± 100 µm), whereas the others did not, probably due to saponification with KOH. FTIR analysis confirmed that cysteine was encapsulated in the microspheres. The microspheres disintegrated at pH 6.18 in a titration test. The TTI pH gradually decreased and showed a sudden color change at pH 6.10, which was similar to the critical pH of microsphere disintegration.

Tailored enzymes as next-generation food-packaging tools

Enzymes have the potential for biotransformation in the food industry. Engineering tools can be used to develop tailored enzymes for food-packaging systems that perform well and retain their activity under adverse conditions. Consequently, novel tailored enzymes have been produced to improve or include new and useful characteristics for intelligent food-packaging systems. This review discusses the protein-engineering tools applied to create new functionality in food-packaging enzymes. The challenges in applications and anticipated directions for future developments are also highlighted. The development and discovery of tailored enzymes for smart food packaging is a promising way to ensure safe and high-quality food products.